Electric tuning device.



E. G. STALNAKER, MINOR.

o. w. STALNAKEB, GUARDIAN. ELEGTRlC TUNING DEVICE. APPLICATION FILED JUNE 21, 191

E. G. STANAKER, MINOR. o. w.-s1.1L1uxn11, GUARDIAN. ELECTRIC TUNING DEVICE.

urLInATIox FILED JUNE 21,1912.

Patented May 12, 1914.

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UNITED sTATEs PATENT oEEicE.

EARL GLEN STALNAKER, OF CHICAGO, ILLINOIS; CHARLES W. STALNAKER, GUARDIAN F SAID EARL GLEN STALNAKER, MINOR, ASSIGNOB T0 CHARLES W. HOFF, 0F CHICAGO, ILLINOIS.

ELECTRIC TUNING DEVICE.

specification bf Letters Patent.

Application filed June 21, 1912. Seria1No. 704,977.

To all fav/0m it may] concern.'

Be it known that I, EARL GLEN STALNAKER, a citizen of the United States, residing at Chicago, in the county of Cool: and State of Illinois, have invented a certain new and useful Improvement inElectric Tuning Devices, of which the following is a full, clear, concise, and exact description, reference-bcing' had to the accompanying drawings, forming a part of this application.

My invention relates to apparatus for adjusting or varying the oscillation-responsiveness of circiits used in high frequency systems of transmitting energy, such as the receiving circuits of wireless telegraph systems. Its object is to provide an apparatus by which the inductance of a circuit, or its static capacity, or both, may be varied so as to make the circuit responsive successively to wireless impulses varying greatly in wave-lengths or periodicity and in intensity; to provide means whereby the wireless impulse itself may automatically lock Athe apparatus in the position in which it has made the circuit responsive to the impulseto be received by it; whereby the apparatus will maintain this adjustment until the message has been received in its entirety; and whereby the apparatus will discontinue this adjustment and make a new adA justment for each succeeding message, regardless of` differences in the wave-lengths or periodicities of the various messages. Also, to provide means whereby the apparatus when locked inapproximately the properly adjusted position, may be more accurately adjusted or attuned by the operator.- f

The .apparatus of my invention is particularlyadapted for use as part of the wireless 'receiving systems shown vin my copending application filed June 15,1912, Serial No. 7 03,814, and is shown in this adaptation in the accompanying drawings, lin whichi lFigure 1 is a side elevation of the preferred form of my tuning apparatus. Fig.

, 2 is an end view of the same, showing the timing mechanism. Fig. 3 is` a partially sectional Vend view of the drum of the apparatus. Fig. 4 shows the manual adjustment. Fig. 5 shows an alternative timing mecha- 'nism. Fig. 6 shows an alternative arrangement of the inductive, contact and driving elements. Fig. 7 is a plan view of Fig. 6.

Irr the drawings, 1 is a brush contacting with a ring 2 mounted on one end of a cylinder or drum 3, which latter is preferably of hard rubber. 3 is a single layer of insulatedcopper wire 4, having the insulation scraped off the surface along lines 5 diagonal of the axis of the cylinder. l

6 is a Contact brush pivoted on a shaft 7 and pressed against the wire on the cylinder by springs 8, the shaft 7 having a square end 7 to keep it from turning in the end bracket `9.

10 is a shaft passing loosely through the cylinder 3, but rigidly fastened to an arm 11. This arm 11 is connected by a screw 12 and lnurled nut 13 to a fork 14 fastened to the end 3 of the cylinder 3, so that the position of thecylinder relative to the shaft may be varied by turning the nut 13 in either direction.

16 is a bearing for the shaft 10.

17, 18 are gears connecting the shaft 7 with a driving shaft 19 which is preferably driven by a clock or an electric motor.

20 is a detent adapted to hold the gear 1S from rotating, but normally hld out of its latching position by the weight of a liquid in a brass tube 21 which engages the hook 22 at one end of the detent. 23 is an electro-magnet which, when energized, will attract a soft iron armature 24 fastened to the other end of the brass tube 21, whereby the tube forces the detent into the latching position.

25 are contact brushes adapted to bear on a considerable arc ofthe exposed wire 4 on the cylinder 3, each brush being connected to a separate section 26 of a condenser. 26 are the other terminals of the same condenser.

In operation, both the in ductance coil 4 and the condenser 26 are preferably connectcd to some part of the same `circuit so that the inductance of this circuitzwill vary with the number of turns of thecoil 4 included in the circuit, while the capacity of the circuit will vary with the number of sections 26 connected to the circuit. If the driving Ishaft 19 is continuously rotated, thevcylin- Wound upon the cylinder dci-'3 will likewise rotate continuously, therehy steadily shifting the points of contact of the exposed lines on the drum with the brushes 6 and 25. Consequently, both the inductance andl the capacity of the circuit to which the apparatus is connected, or in other words the resonance of this circuit, will be continually varied. 'It this is done in the presence of a series of wireless impulses (sucli as the dots and dashes comprising a wirelessv message) the rst impulse which finds the apparatus in the position where 'it makes the circuit responsive to these impulses, will actuate any sensitive wave-responsive device included in the circuit. Then if this wave-responsive device, such as a detector 27, is arranged'to close another circuit (as in my copending application, Serial No. 703,814), it 4may close a battery circuit through the magnet 23. In doing so, it will cause the pivoted tube 21 to force the detent 20 into engagement with the gear 18, thereby halting the rotation of the cylinder 3 and consequently stopping a further change in the adjustment of the inductive coil 4 and thev condenser 26. In other words, it will halt the varier in a position in which the varier makes the circuit resonant or responsive to the wireless impulses.

lVhen the wireless impulse which actuated the wave-responsive device to close the circuit ofthe magnet 23 ceases, this magnet will release its armature 24, thereby allowing the tube 21 to tilt until its upper edge strikes the hook 22 of the detent. In this position, the weight of the armature 24 would not be sufficient to overbalance the weight of the detent 20, hence it would not immediately raise the detent out of its latching position. ,However, the' slowly flowing liquid in the tube would now How back toward the armal ture end of the tube until its added weight would overbalance that of the detent, thus raising the'latterout of engagement with the gear 18. By usinga sticky liquid, the time required for ittomove the detent may be made considerably greater than the ordinary interval between the successive dots and dashes in a wireless message, so that the magnet will again and again be energized before the detfent'has been raised, thereby holding the tuning apparatus in a ixed position until the message has been completed.

It will be obvious that with the arrangement justdescribed, the tune-varying coil and condenser will be automatically adjusted by the first Wireless wave to which the circuit including this apparatus is rcsponsive. However, this adjustment may only be approximate and not so accurate as to insure best resultswith the receiving apparatus used. I therefore preferably pro-i vide a manual adjustment by which the operator can give the tune-varying apparatus a further and) more delicate adjustment; as i by turning the knurled nut 13, which will rotate the cylinder 3 slightlywliile the shaft 10 is held rigidly through the action of the detent 20 on the gears 17 and 18.

Instead of depending upon a sluggish liquid to provide the desitrably slow releasing of the detent, whereby the latter is held in engagement for a predetermined interval of time, this time interval may be provided by using a thermal circuit-controller for the stop magnet 23, as shown in Fig. 5. In this case the relay 28, actuated by a waveresponsive device such as a detector 27, closes a battery circuit 29 through a heating coil 30, which is made of fine enameled wire' and sealed into the bulb 31 of a thermometer 32. When the circuit is thus closed, the heating of the wire 30 expands the mercury 33 in the bulb, causing the mercury to rise in the tube 34. .In so doing, it closes the circuit 35, 36 of a battery 37 connected. to the stop magnet 23. Upon cessation of the impulse which actuated-the relay 28, the current through the heating coil 30 will cease,

likewise, but the mercury expanded into the line tube 34 will be slow in contracting suiiiciently to cease contacting with the wire 35; hence the detent will be held in latching engagement with the varier for a suflicient interval of time to enable a succeeding wireless impulse to again actuate the relay 28 and the heating coil30. When the receivable message is ended, the mercury will gradually recede from the tube 34, breaking the circuit to the magnet 23 and releasing the detent; whereupon the tuning apparatus will resume its round of inductanceand capacity-varying until checked by an impulse stopping itin the position where it attunes the circuit to the next message.

If the apparatus is to be used when an operator is on duty, the timing device may not be needed. In this case I provide a simple pawl 38 which will hold the detent 20 in the latched position until the operator has recorded the message.

While I preferably rotate the inductive coil of my apparatus and vary the connections by having a brush contact with spirally disposed bare spots on the surface of the coil, I do not wish to be limited to this particular construction, as various methods could be used for varying the number of turns of the inductive coil which are included in the circuit. For instance, the coil vmay have a single row of bare spots arranged parallel to the axis (as at 39 in Fig. 7 in which case the contact can be made by reciprocating a brush 40. This may be done by meshing a pinion 47 with a gear 41 on the driving shaft 42, mounting a crank .50 on the same shaft 49 with the pinion, and

connecting this crank 50 by a pitman 5l to the brush 40.

Instead of using a clock or motor as'the driving mechanism, the varier' of my invention may be driven by a weight, as in Fig. 6, where the weighted arm 44 carries a pawl 5 45 engaging a ratchet wheel 46. Upon raising the weighted arm, its weight will turn the ratchet wheel 46 yand the shaft 42 to which the ratchet 46 is fastened, thereby rotating the gears 41 and 47, thus rotating the crank 50`a`nd moving the brush 40 back and forth along a guide rod 48. In this way the operator can. rapidly oscillate the varier through its entire range so as greatly to reduce the time required for finding the position in which the tuning apparatus brings the circuit of which it forms a part, into resonance or syntonism with the wireless waves. n

While I have shown the device of my invention as simultaneously varying the inductance of a rotating coil and the capacity of a condenser connected to the coil, I do not wish to be limited to this particular application, as the same combination of a wave-responsively actuated detent (which detent is quick in acting but slow in releasing) may beV applied to other types of apparatus for continuously varying the resonance or oscillation-responsiveness of a circuit;

30 c. to any apparatus by which a circuit may be made successively responsive to, or brought into syntonism with, oscillations of widely varying periodicity. Nor do I wish to be limited to a tuner for receiving apparatus,

asitwill be evident thatlthe device of my invention can be used for adjusting the resonance of a circuit regardless of whether or n ot this is a receiving circuit. So also, I do not wish to be limited to apparatus in which the wave-responsive device is actuated by a wireless impulse emanating from a distant point, as it will be evident that the source of this impulse could be near to my tuning apparatus without departing fromV the spirit of my invention. Neither do I wish to loe limited to the particular forms of manual adjustment, latches or other details shown by me, as numerous modificaticns could be made in the same without departing from the spirit of my invention.

lVhat I claim as new and desire to cover by Letters Patent is:

1. Wireless tuning apparatus, including a rotatable inductancecoil` having bare spot-s helically disposed on the exterior ot die coil, astationary Contact brush adapted to contact successively With the bare spots on successive turns of the coil as the latter is rotated, a shaft for the said coil, and an adjustable connection betweenthe said coil and the said shaft.

42. IlVireless tuning apparatus, including an inductance coil, a brush adapted to contact with the exteriorv of the coil, power-actuated mechanism for'continuously and reciprocatingly shifting the point of contact between the brush andthe coil to fvary the linductance of the coil, a detent forv halting the said mechanism, and manual means for shifting the said point of contact when the said mechanism is halted.

3. Wireless tuning apparatus, including a rotatable inductance coil having bare spots helically disposed 011 the exterior of the coil; a stationary contact brush adapted to l contact successively with the bare spots on successive turns of the coil as the coil is 1'0- tated; mechanism vfor rotating the said coil, a detent for halting the said mechanism, and

manual adjusting means for moving the said coil with respect to the said mechanism when the latter is halted. i

4. Wireless tuning apparatus, including a rotatable inductance coil having bare spots helically disposed on the exterior of the coil, a stationary contact brush adapted to contact successively with the bare spots on successive turns of the coil as the latter is rotated, a shaft for the said coil, an arm carried by the said shaft and rigid therewith, and an adjustable connection between the said arm and the said coil.

5. Wireless tuning apparatus, including.. an inductance coil, a brush adapted to contact with the exterior of the coil, and power actuated mechanism for continuously and reciprocatingly shifting the point of contact between the brush and the coil, thereby varying the inductance.

6. Wireless tuning apparatus, including a rotatable inductance coil having bare spots helically disposed on the exterior of the coil,

a stationary contact brush adapted to contact successively with the bare spots on successive turns of the coilas the coil is rotated, and means for rotating the said coil.

7. Wireless tuning apparatus including an inductance coilt having bare spots helically disposed on the exterior of the coil; a

contact brush; the said coil and brush relatively rotatable, the brush adapted to contact successively with the bare spots on successive turns of the coil upon relative rotat-ion of the coil and brush; and means for effecting said relative rotation.

8. Wireless ktuning apparatus including an inductance coil having barespots helically disposed on the exterior ot the coil; acontact brush; the said coil and brush relatively movable, the brush adapted to contact 120 successively with the bare spots on successive turns of the coil upon relative movement of the coil and brush; and means for .effecting said relative movement.

9. Wireless tuning apparatus including an inductance coil having bare spots helically disposed on Athe exterior of-the coil, a

stationary contact brush adapted to contactsuccessively with the/bare spotson successive turns of the coil as the, coil 1s rotated; a 13,0

sectional condenser; connections from the successive sections of the said condenser to successive portions of the coil, and means for ,rotating the said coil.

l0. Wireless tuning apparatus including an inductance coil havingbare spots helically disposed on the exterior of the coil; a contact brush; the said coil and brush relatively rotatable, the brush adapted to contact successively Withthe bare spots on successive turns of the coil upon relative rotation of the coil and brush; a sectional condenseigthe sections thereof connected to successive portions of the coil; and means for effecting said relative rotation. 

